Adjustable support for school furniture



(No Model.) 2 Sheets-Sheet I L. B. COBB.

ADJUSTABLE SUPPORTFOR SCHOOL FURNITURE. No. 577,720. Patented Feb 23, 1897,

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ADJUSTABLE SUPPORT FOR SCHOOL FURNITURE.

Patented Feb. Z3,1897,

Wit EssEs.

-UNITED STATES PATENT Orricn.

LEANDER B.-COBB, OF EVERETT, MASSACHUSETTS, ASSIGNOR TO THE CHANDLER ADJUSTABLE CHAIR AND DESK COMPANY, OF BOSTON,

MASSACHUSETTS.

ADJUSTABLE SUPPORT FOR SCHOOL FURNITURE.

SPECIFICATION forming part of Letters Patent No. 577,720, dated February 23, 189'7. Application filed December 5, 1895. Serial No. 571,154. (No model.)

To all whom it may concern:

Be it known-that I, LEANDER B. COBB, a citizenof the United States, and a resident of Everett, in the county of Middlesex andState of Massachusetts, have invented new and useful Improvements in Adjustable Supports for School Furniture, of which the following,

' taken in connection with the accompanying drawings, is a specification.

This invention relates to improvements in adjustable supports for school furniture; and it consists in special mechanism for quickly adjusting the furniture to the height of the person using it, as will hereinafter be more fully shown and described, reference being had to the accompanying drawings,wherein Figure 1 represents a side elevation of a school-desk provided with my adjustable support. Fig. 2 represents an enlarged crosssection on the line 2 2 shown in Fig. 1. Fig. 3 represents a vertical section on the line 3 3 shown in Fig. 2. Fig. 4 represents a vertical section on the line 4st shown in Fig. 2. Fig.

5 represents a rear view of Fig. 4.

' side vertical Similar letters refer to similar parts whereever they occur on the different parts of the drawings.

A A represent the standards or legs secured to the floor as usual.

B represents the desk, to the under side of which are secured the downwardly-projecting plates or brackets C C, which are vertically adjustable relative to the standards A, as shown. 1

Each standard A has a vertical slot A, and

each desk-bracket C is also made with a similar vertical slot C, as is common in devices of this kind. Each standard has on its outguide-faces A A, preferably beveled, as shown in Fig. 2, against which the correspondingly-shaped brackets C are guided and secured in place after the height of the desk has been adjusted.

On one side of the interior of the slotted portion 0' of each bracket 0 is a cog-rack or toothed surface C, the teeth of which mesh into the teeth of pinions D D, secured to opposite ends of the shaft E,which is journaled in bearings A A on the standards A A, as shown in Figs. 2, 3, 4, and 5.

To the shaft E is secured inside one of the bearings A a worm-wheel F and inside the opposite bearing A a collar or similar abutment G, as shown in Fig. 2.

In engagement with the worm-wheel F is a worm H, secured to or made in one piece with a shaft it, that is journaled in hearings on one of the standards A, as shown in Figs. tand 5.

H in Fig. 5 is a crank, hand-wheel, or other similar device permanently or detachably secured to the end of the shaft h, as shown.

Each desk-bracket C has on its outside a tapering face or surface C (shown in Fig. 4,) against which is clamped a correspondinglyinclined plate or washer I, which is held in contact with said inclined surface 0 by means of a nut K, screwed on the outer screwthreaded end of the shaft E and preferably located in a cup-shaped recess 1' on said washer, as shown in Figs. 1, 2, and 4.

If it is desired to raise or lower the desk, all thatis necessary to do is to first loosen the nuts K K, after which the worm-shaft h is turned by means of its crank H in the de sired direction, causing the pinion D, by engaging the rack C", to raise or lower the brackets C C and the desk more or less, as may be needed.

When so adjusted to the desired position, the brackets C are secured to the standards A by tightening the nuts K, although this is not absolutely necessary,as the worm H serves as a look by engaging the worm-wheel F and thus holds the brackets from moving relative to the standards.

Having thus fully described the nature, construction, and operation of myinvention, I Wish to secure by Letters Patent and claim- 1. I11 an adjustable desk, the combination with slotted vertical standards, of brackets secured to the movable desk to have vertical adjustment in the slotted ways of said standards, an adjusting-shaft journaled in bearings in said standards and carrying pinions meshing with racks on the movable brackets, a worm-gear upon'said shaft, a worm meshing with said gear and carried by a shaft journaled in supports upon one of the standards, clam ping-plates loosely mounted on the ends of the adjusting-shaft and bearing upon outer, tapering surfaces on the standards, and clamping-nuts on the threaded ends of said shaft lying in cup-shaped recesses in the outer faces of the clamping-plates, substantially as described.

2. In an adjustable desk, the combination with standards A, bearing vertically-slotted Ways A, of desk-brackets G movable in said Ways and having outer, tapering faces 0 an adjusting-shaft E jonrnaled in bearings on the standards and carrying pinions D which mesh with racks C on the desk-brackets, clamping-plates I loosely mounted on the shaft and provided with faces corresponding to the tapered faces 0 and clamping-nuts K I turned on the threaded ends of the shaft and lying in cup-shaped recesses in the outer faces of the clamping-plates, substantially as described.

In testimony whereof I have signed my name to this specification, in the presence of two subscribing Witnesses, on this 30th day of November, A. D. 1895.

LEANDER B. COBB. Witnesses:

ALBAN ANDREN, CHARLES A. HARRIS. 

